I think part of the reasons sex scenes tend to stick out as gratuitous is that a lot of authors, who are otherwise extremely skilled at writing, simply can't write them well. So, they end up being ridiculous and making readers wish the author would get back to the gunfights/car chases/whatever already.
I admit I'm guilty of skipping sex scenes in books, not out of any sort of prudishness but because the writing made me laugh and it was breaking my suspension of disbelief.
|